1. Field of the Invention
The present invention relates to an active matrix type tactile and visual display device, and more particularly, to a tactile and visual display device in which a portion generating a tactile sensation and a portion generating a visual sensation are integrated.
2. Discussion of Related Art
While the five senses are the visual, auditory, olfactory, gustatory and tactile senses, current display devices focus on the transmission of visual information. That is, they digitize sound and an image of a phenomenon or an object to transmit virtual information. Currently, demand for the transmission and exchange of information related to other senses is on the rise. Particularly, developments in telecommunications have led to the popularization of TV and Internet shopping malls. If Internet shopping malls provide tactile information such as roughness and friction as well as visual information, this will expand and enrich the market.
Current methods of quantifying and providing information on the tactile sense fall short of meeting the rising demand for such information. Research into a method of interchanging information between media and humans using the five senses has found that the tactile sense is very sensitive to force, vibration, temperature, etc., and thus does not easily lend itself to quantification and simulation.
Conventionally, a mechanical simulator array has been used to simulate the surface texture of an object. When the mechanical simulator array is used, a DC motor, a piezoelectric device, a shape memory alloy actuator, an ultrasonic vibrator, an air jet, a pneumatic actuator, a Peltier device, a surface acoustic wave device (a device using acoustic radiation pressure), a pressure valve device, an ionic conducting polymer gel film, etc., are used to stimulate mechanoreceptors in the skin.
Besides mechanical stimulators, there has also been extensive research into the use of electromagnetic force. For example, H. Tang, and D. J. Beebe disclose the use of an electrostatic force without applying mechanical pressure in “A Microfabricated Electrostatic Haptic Display for Persons with Visual Impairments,” IEEE Transactions on rehabilitation engineering, Vol. 6(3), (1998), pp 241-248. Also, M. B. Khoudja, M. Hafez, J.-M. Alexandre, A. Kheddar, and V. Moreau disclose the use of an electromagnetic micro-coil in “VITAL: A New Low-Cost Vibro-Tactile Display System,” Proceedings of the 2004 International Conference on Robotics & Automation (2004), pp 721-726. H. Kajimoto, N. Kawakami, and S. Tachi disclose the use of electrostimulation in “SmartTouch: Skin to Touch the Untouchable,” IEEE Computer Graphics and Application, Vol. 24 January/February (2004), pp 36-43. K. A. Kaczmarek, M. E. Tayler, and P. Bach-y-Rita disclose the use of direct current (DC) in “Pattern Identification On a Fingertip-Scanned Electrotactiel Display,” Proc. of the 11th Symposium on Haptic Interfaces for Visual Environment and Teleoperator Systems, Haptic Symposium 2003 (2003), pp 40-46. This literature concerns the generation of attraction, repulsion, and friction to stimulate the skin. The idea of producing artificial texture using electrostatic force was suggested by Mallinckrodt, et al. (E. Mallinckrodt, A. L. Hughes, and J. W. Sleator “Perception by the Skin of Electrically Induced Vibration,” Science, Vol. 118 (1953), pp 277-278) and by Strong, et al. (R. M. Strong, and D. E. Troxel “An Electrotactile Display”, IEEE Trans. Man-Machine Systems, Vol. 11(1) (1970), pp 72-79) since it can generate a tactile sensation with a simple structure and, unlike current, it does not have a direct effect on humans.
According to Tang, et al., an electrostatic haptic display with three 7×7 electrode arrays is fabricated on a 4-inch Si wafer using photolithography, and a voltage is applied to produce a tactile sensation and thus form a Braille display. However, in the display, the wiring of each electrode is not easy, and resolution is insufficient to produce the texture of a material. Further, it is not easy to represent a variety of tactile information using the above structures.